Sum Lines
Fill every run so it adds up — no digit repeats within a run.
Interactive lesson1 / 4
Rule 01
Fill every white square with a digit 1–9.
Tap a square to select it, then type a digit or use the number pad. Black squares hold the sum clues and never take a digit.
All rules
Rule 01Fill every white square with a digit 1–9.
Tap a square to select it, then type a digit or use the number pad. Black squares hold the sum clues and never take a digit.
Rule 02Each run adds up to its clue.
A run is an unbroken line of white squares reading across or down from a black clue cell. The clue shows the total those squares must sum to once every one of them is filled.
Rule 03No digit repeats within a run.
Every square belongs to one across run and one down run. A digit may appear in both — but never twice in the same run, across or down.
Tap a run to select it, tap again to switch across/down · type 1–9 · backspace clears
Got it — play